Chuck.



S. M. COFFMAN.

CHUCK.

APPLICATION FILED FEB.9.1914.

Patented June 1, 1915.

IWI/elia??- i Sai/zzZ/ @a/726W i THE MORRIS P CD., PHOTO-LITHU., WASHINGTON, D. C.

Y side elevation of the upper portion of a ernten.

SAMUEL M. COFFMAN, OF KANSAS CITY, MISSOURI.

CHUCK.

Specification of Letters Patent.

Patented J une 1, 1915.

Application led February 9, 1914. Serial No. 817,531.

To all 'whom 'it may concern Be it known that I, SAMUEL M. CorrMAN,

a citizen of the United States, residing at Kansas City, in the county of Jackson and State of Missouri, have invented certain new and useful Improvements in Chucks, of which the following is a specication.

My invention relates to improvements in chucks, and relates more particularly to that style employed by watch-makers for turning, truing, grinding, and polishing the pivot end of watch and clock arbors and staffs. There are two chucks now in general use for this work one of which has a waxcenter, the other a split end. With the first it is a slow and tedious operation to properly center a staff, while with the second it is frequently impossible to perfectly center the staff owing to one of the split members of the chuck springing outwardly more than its companion. A further objection is that it is impossible to measure the full length of a staff while in position in either the wax or split chuck. All of these objections are overcome by employing the present chuck, as a staff can be quickly and accurately centered, and its entire length be readily ascertained without removing it from the chuck.

Referring now to the accompanying drawing which illustrates the invention: Figure 1 represents a perspective of the chuck. Fig. 2 is an enlarged central longitudinal section of the same. Fig. 3 is a lathe withV the chuck in position thereon. Fig. 4 is a detail side elevation of a supplemental chuck, forming part of the invention. Y

1 designates the upper portion of a lathe provided with a hollow spindle 2, through which my chuck extends, said spindle being driven byA a step pulley 3.

4c designates the stock of my chuck, which is provided at its rea-r end with screwthreads 5 and a groove 6, whereby it is secured in spindle 2, and caused to rotate therewith. The forward portion 7 of the stock is enlarged and tapered to form a seat for a member 8 having universal movement.

VThe forward end of the stock is reduced and tapered so that theforward end of a sleeve 9, loosely embracing the same, will be free to move laterally to a limited extent without contacting with said tapered end. Sleeve 9 has ball segment ends 10 and 11 which latter is swiveled in an annular bearing 12, connected to a collar 13 by screws 14, which extend through slots 14a in a socket l5.

Member 8 may be made in various ways to obtain universal movement, but consists preferably, of socket 15, a ball 16, and a jaw-carrying member 17 swiveled in the forward end of ball 16 and upon the ball segment end 10 of sleeve 9. Socket 15 lits friction tight upon the tapered seat of the enlarged portion 7, so that it will rotate with thestock and is provided with peripheral shoulders 18, 19, for a purpose hereinafter specified. Ball 16 and member 17 have tapered bores 20, 21, so that they may turn in their sockets to a limited degree without contacting with sleeve 9. Member 17 has a pair of oppositely-disposed jaws 22 for supporting a supplemental chuck 22a, which is reliably locked in said jaws by a pivoted clamping member 23, adjusted by a set-screwQl, extending through a threaded aperture in the rear end of said clamping member and engaging one of the jaws, see Fig. 2.

25 designates a clamping-nut rotatably mounted upon socket 15 and provided, respectively, at its rear and front ends with annular shoulders 27 and 28, which latter normally abuts against shoulder 19 and limits the forward movement of the clamping-nut. Said clamping-nut is also provided with internal threads 29, which engage peripheral threads on collar 13. By

rotating the clampingnut in one direction, the engaging threads move collar 13 backwardly and cause it to move bearing 12 and sleeve 9 therewith, and thus lock ball 16 and member 17 in their respective sockets, and by rotating the clamping-nut in the opposite direction collar 13 is carried forward and relieves the pressure on ball 16 and member 17, so they will be free to turn in their sockets while a stalf is being adjusted to bring it in axial alinement with the chuck. The parts, however, are normally kept under slight tension to prevent the ball and member 17 from turning too freely in their sockets, by an expansion spring 30 interposed between shoulders 18 and 27. Stock 4 has an axial bore extending therethrough in which a pump-center 31 is slidably arranged, the latter being held fitting within a socket 35 in the forward' end of the pump-center and provided at its forward end with aicavity 36 for engaging and centering the rear end of a staff 38. Bearing 34 is removable, so that other bearings containing larger or smaller cavities for thereceptionof larger or smaller staffs may be substituted therefor.

The pump-center is providedat its rear portion with a stem 39, whereby it may be slid forward or backward to engage or disengage a staff, or be lockedl to the stock. Said stem has a threaded forward end adjustably engaging an internally threaded bore 41 in the rear end of the pump-center. Stem39 is also provided at its forward portion with a conical expander 42 engaging the split rear'end 43 of the pump-center, so that after the latter hasbeen'properly ady justed it may be locked by expanding its toV split portion 43 into frictional engagement with the interior of the stock. Stem 39 is provided at its rear end with Va knob 44,

whereby it is manipulated.

A45 designates a sleeve loosely embracing the rear portion of stem 39 and adapted to fit in spindle 2, said sleeve being provided Vat its rear. portion with a bearing 46 which frictionally engages the interior of the spin- *35 dle so that it will rotate therewith.

The ypump-center and its stem are norpressed forward by an expansion spring 47 interposed between the rear portion of; sleeve 45 and a collar 48, which latter is fixed to the stem and slidably engages the forward end of the sleeve to form a bearing therefor.

When truing or polishing the pivot of a watch or a clock staff, I prefer to employ the crescent-shaped supplemental chuck 22, so thatl almost the entire staff may be exposed for taking measurements, by turning the cut-away side of Said chuck toward the workman. Chuck '22a has an opening 49 for the reception of the staff, and in order that said chuck may firmly grip the staff I render it slightly resilient by slitting it at opposite sides of opening 49 and forming the inner end of the slit. When grinding the staff Iof a balance-wheel 5l, I prefer to use a circular supplemental chuck 22h, as shown in Fig. 2, to prevent the workmans sleeve from'coming in contact with said .balance-wheel while it is being rapidly ro- ,.tated. A number of supplemental chucks `with different size openings to receive different size staffsv are supplied with each chuck.`

In practice, a staff is placed through the opening 4inthe supplemental chuck and thel pump-'center is moved forward so that its l1,141.1,6'1La bearing 34 will engage and center therear end Yof! the staff as shownin Figs. 2 and 3.

The forward end of the stalf is centered by.

the pump-center, Vas shown in Fig. 2. The

Vparts of member 8 are then locked from independent movement so that the stan will be` reliably held in alinement with the pumpcenter'whilebeing' ground or polished. If it is desired to'measure thelength of the staff without removing it from Vthe supplementalchuck, it is only necessary to unlock the pump-center and'slide it back, so that its bearing'34wwill'be carried back out of engageinentwith the staff, and ythen lock the same by turning knob 44 tothe right.

' Having thus described my invention, what I claim is Y f l. In a device of the character described, a stock, and La `member .having universal movementfand consisting of a socket secured to the stock, a ball adjustably mounted in said socket, and a jaw-carrying member ad'- justably mounted in the ball.; means carried by the jaws for engaging the work to be operated upon, yielding means for normally retarding independent movement of the parts constituting said member, and means for locking said parts vfrom independent movement.

soV

2. Ina device of the character described, Y

rear portion ofthe stem, a collar on saidV stem and slidably mounted in the sleeve, and an expansionl spring interposed between said vcollar and the rear end ofthe sleeve.

3. In a device of the character described, a stock having a forwardly tapered end, a sleeve free to move longitudinally and laterally upon said tapered end, said sleeve having ball segment ends, a supplemental chuck-carrying member having universal.

movement and mounted upon the stock and the forward 5 segment of the sleeve, and meansengaging the rear segment Yof the sleeve" and said member to lock the latter from universal movement.

4. In a device of the character described,

a stock having a forwardlyl tapered end, a sleeve free to move longitudinally and latioo lois u lio erally .uponV said tapered end, a supple-V mental chuck-"carrying member having universal movement and mountedv upon the stock andthe forward end of the sleeve, va nut rotatably mounted -upon said member,

said nut having internal threads, and an externally threaded member engaging the rear end of the sleeve and the threads of the nut, whereby when the latter is rotated in one direction said externally threaded member causes the sleeve to lock the rst member from universal movement.

5. In a device of the character described, a stock having a forwardly tapered end, a sleeve free to move longitudinally and laterally upon said tapered end, said sleeve having ball segment ends, a supplemental chuckcarrying member having universal movement and mounted upon the stock and the forward segment of the sleeve, an internally threaded nut rotatably mounted upon said' member, a spring interposed between said nut and the member to secure the latter from accidental movement, and means engaging the rear segment of the sleeve and the threads of the nut, whereby when the latter is rotated in one direction the sleeve will be drawn backward to firmly lock the member from universal movement.

In testimony whereof I affix my signature, in the presence of two witnesses.

SAMUEL M. COFFMAN. Witnesses:

F. G. FISCHER, L. J. FISCHER.

C'opies of this patent may be obtained for iive cents each, by addressing the Commissioner of Patents, Washington, D. G. 

